JPS61266363A - Spray refractories and spraying method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a spray refractory used for spray lining or spray repair of industrial iron-making furnaces, and a method for spraying the same.

[Conventional technology] The conventional spraying method is called the wet spraying method, in which the spraying material is mixed with water to form a slurry before being sprayed.
and the dry spraying method, in which water is added to powdered spray material at the spray nozzle.
Two methods have been widely used.

[Problems to be Solved by the Invention] However, these spraying methods also have advantages and disadvantages, including the following problems. In other words, the wet spraying method requires a long kneading time to form a slurry, making it inconvenient for emergency repairs.Also, it is difficult to adjust the construction thickness, and even in hot spraying, it is difficult to set the construction thickness to 30 mm or more. difficult,
For this reason, it is currently impossible to repair thick walls where the lining bricks often fall off in industrial kilns.

Unlike the wet spraying method mentioned above, the dry spraying method has the advantage of being relatively easy to spray. However, it generates more dust than the wet spraying method, creating a poor working environment and lowering the adhesion rate. There are problems such as low performance.

However, at present, the dry method is used for converters, ladles, RHs, tie pads, etc. due to the ease of spraying.

In view of the above-mentioned problems, there is a need for a spraying material and spraying method that produces less dust, has a high adhesion rate, and has good workability, and various studies are being carried out.

In other words, the blast furnace, hot metal trough, pig iron mixing car, etc. should be sprayed immediately before spraying.
The method used is to pre-knead ~3% water and spray it.

Although alumina cement-based binders are used in these sprayed materials, since they are hydraulic binders, there is a problem in that the usable life after pre-mixing is limited. Furthermore, there are equipment problems such as the need for a crosstalk machine, and it lacks simplicity.

In addition to these, alkali phosphates and alkali silicate salts are used as binders for spraying materials, and these solutions are added to refractory powder to moisten it and reduce the generation of dust. Attempts have been made, but they have not been put to practical use because of storage problems such as curing due to reaction with refractory powder or CO2 gas in the air.

[Means for Solving the Problems] Therefore, the object of the present invention is to improve the above-mentioned spraying method to provide a spraying material and a spraying method thereof that are easy to store, generate less dust, have a good adhesion rate, and are simple. The aim is to improve the working environment and perform efficient spraying.

Therefore, in the present invention, Rz O/
S i Ot f) %R ratio is 0.4 to 1.2 (R2
O represents an alkali metal oxide) and Bias/Si
It is an object of the present invention to provide a spray refractory comprising an outer 0.5 to 10% by weight of an alkaline borosilicate solution having a molar ratio of ng to 0.01 to 0.3.

Furthermore, the present invention adds R, O/5i to 100% by weight of the refractory powder.
An alkaline borosilicate solution having a molar ratio of Ot in the range of 0.4 to 1.2 (RzO represents an alkali metal oxide) and a molar ratio of B2O3/5iOz in the range of 0.01 to 0.3 is .5 to 10% by weight is added and mixed, the refractory powder is pre-wetted, and when spraying the refractory powder, a curing agent is added at the spray nozzle and sprayed. The present invention provides a method for spraying refractories.

[Function] The most important feature of the spray refractory of the present invention is R,0/S
I Oz% Le ratio is 0.4 to 1.2 and Bz
The purpose is to add an alkaline borosilicate solution having a molar ratio of Os/Sin in the range of 0.01 to 0.3 to the spray material. This alkaline borosilicate solution is different from conventional alkali silicate, alkali phosphate, alumina cement, etc. in that it does not gel due to CO2 gas in the air, does not easily react with various refractory powders, and does not have self-hardening properties. They have different characteristics.

This borosilicate alkaline solution has R2O/S! The molar ratio of Ot is set to 0.4 to 1.2, and the molar ratio of B z O2/S
i Oz f) By setting the molar ratio to 0.01 to 0.3, long-term stability of the solution can be obtained, and properties such as low reactivity with various refractories at room temperature and excellent adhesive strength can be obtained. .

Here, R2O/S i Oz of the borosilicate alkaline solution
If the molar ratio is less than 0.4, the sprayed refractory will change significantly over time and will tend to solidify, which is not preferable.

In addition, R2O/SiOz of borosilicate alkaline solution
If the molar ratio exceeds 1.2, the adhesive strength of the spray refractory will be poor. In addition, if the BxO*/SiO* molar ratio of the alkaline borosilicate solution is less than 0.01, the refractory for spraying will change over time and become more likely to solidify, which is undesirable. When the ratio exceeds 0.3, the stability of the alkaline borosilicate solution tends to decrease, and the adhesive strength tends to decrease.

Although the concentration of alkali borosilicate can be varied, it is preferably such that the solid content concentration of SiO□ is in the range of 10 to 30% by weight.

As the alkaline borosilicate solution, for example, potassium borosilicate solution, sodium borosilicate solution, stium borosilicate solution, etc. can be used.

For the spray material, the amount of alkaline borosilicate solution added is preferably 0.5 to 10% by weight based on 100% by weight of the refractory powder.If the amount of alkaline borosilicate solution added is less than 0.5% by weight, a large amount of dust will be generated; Moreover, it is not preferable because it is inferior in terms of bonding strength and adhesive strength.

Furthermore, if the amount of the alkaline borosilicate solution added exceeds 10% by weight, the refractory powder will go beyond a wet state and turn into a slurry state, which will significantly impair workability during spraying, which is not preferable.

The refractory powder used in the present invention can also be acidic or neutral refractory materials such as silica, alumina, and zircon, as well as basic refractory materials such as maguro and magnesia. There is no problem.

Further, thickeners such as clay and organic thickening agents can be added and blended as necessary.

The curing agent used in the present invention can be added in the same manner as the addition of water at the nozzle, which is carried out in conventional dry spraying methods. That is, in the conventional dry spraying method, water was simply added at the nozzle, but in the method of the present invention, an aqueous solution of a hardening agent or a hardening agent dispersed in water is added at the nozzle instead of water.

Examples of hardening agents that can be used in the method of the present invention include alkali phosphates such as sodium hexametaphosphate, monobasic sodium phosphate, monobasic calcium phosphate, monobasic magnesium phosphate, monobasic aluminum phosphate, silicon phosphate, and phosphoric acid. Examples include phosphoric acids such as acids, and conventionally known hardening agents for sodium silicate such as sodium aluminate, sodium bicarbonate, Ca(OH)2, and Portland cement.

The present invention is a construction method that can be used both hot and at room temperature.
When performing hot construction or room temperature construction,
It is necessary to appropriately select the curing agent and adjust the concentration of the curing agent. In other words, in the case of hot construction, a curing agent that has a relatively slow curing rate due to the addition of heat curing, such as an alkali phosphate salt, can be used, but in the case of room temperature construction, heat curing cannot be expected. In order to improve body shape retention, it is desirable to use a curing agent that has a fast curing rate, such as monoaluminum phosphate, phosphoric acid, and sodium aluminate.

The concentration of the curing agent is determined by the liquid viscosity and is 300 centivoise (
cp) or less, and if it exceeds 300 ep, the fluidity decreases, the dispersibility of the curing agent into the spray material deteriorates, and a uniform spray layer cannot be formed, so it is not preferable.

[Example] A spraying test was conducted after three months of production of the sprayed refractories of the present invention having the compounding ratios shown in Table 1 below. The amount of spraying was 50 kg per time, and the spraying was carried out on the surface of a 1s x 1 wheel firebrick panel, and the adhesion rate and amount of dust generated at hot (600° C.) or room temperature were observed. Before spraying, the curing agent was dissolved in a water tank at a predetermined concentration, and during spraying, it was added through the nozzle, and the amount added was adjusted while observing the surface of the sprayed layer. The hardening agent used in this example was dibasic sodium phosphate during hot spraying, and a rapidly hardening phosphoric acid solution was sometimes used during room temperature spraying to maintain shape retention. The results obtained are also listed in Table 1. .

As is clear from the above examples, the sprayed refractories of the present invention exhibited good fluidity, with no hardening of the material observed even after 3 months after manufacture. The amount of dust generated when material is introduced into the material tank has been reduced to less than 1/10 of that of conventional products, and the adhesion rate has improved by 10 to 20%. Furthermore, the structure of the constructed body produced by the method of the present invention was more dense than that of the conventional product constructed body.

[Effect of the invention〕 The effects of the present invention are as follows.

(1) The spraying operation is easy.

(2) Almost no dust is generated during spraying.

(3) Very good adhesion rate.

(4) Long storage period.

Claims (1)

[Claims] 1. The molar ratio of R_2O/SiO_2 is 0.4 to 1.2 (R_2O represents an alkali metal oxide) in 100% by weight of refractory powder, and the molar ratio of B_2O_3/SiO_2 is 0. A spray refractory comprising an outer 0.5 to 10% by weight of an alkaline borosilicate solution in the range of .01 to 0.3. 2. The molar ratio of R_2O/SiO_2 to 100% by weight of refractory powder is 0.4 to 1.2 (R_2O represents an alkali metal oxide), and the molar ratio of B_2O_3/SiO_3 is 0.01 to 0.3. Add 0.5 to 10% by weight of an alkaline borosilicate solution in the range of 0.5 to 10% by weight and mix, make the refractory powder wet in advance, and add a curing agent at the spray nozzle when spraying the refractory powder. A spraying method for spraying refractories, characterized by spraying the sprayed refractories.